In recent years, carbon fiber reinforced polymer (CFRP) has received extensive attention in the industrial field, due to its excellent performance. Laser cleaning technology for pretreatment of carbon fiber reinforced polymer is beneficial to the improvement of the surface properties and the bonding strength of the interface. The technology of detection assessment is the key to ensuring the quality of laser cleaning, and the core of the automation and the integration of laser cleaning device. Laser induced plasma spectroscopy can quickly analyze the changes of surface elements and realize the on-line detection of surface state of laser cleaning. It has a wide application prospect in the field of laser cleaning. In this paper, laser pulse which was produced by Nd:YAG pulse laser, with a wavelength of 1 064 nm,was used to induce plasma under the condition of room temperature and atmospheric pressure. Modified ME5000 grating spectrometer was used to collect the plasma spectrum. Laser induced plasma spectroscopy was used to detect the process of laser cleaning of carbon fiber reinforced polymer online. The plasma spectrum of air was obtained, and the influence of plasma spectrum was investigated. It was found that the spectrum of 350~700 nm can be used to analyze the surface composition of CFRP. The surface morphology observed by electron scanning microscope and the elements measured by X-ray electron spectroscopy were used to characterize the detection results of plasma spectrum. In order to obtain the threshold of removing the surface material completely of carbon fiber reinforced polymer, the plasma spectrograms under different laser energy and different cleaning times were collected. The relationship between laser cleaning quality and the main elements and their intensity changes of plasma spectrum were studied. The results showed that the 393.3 nm S (Ⅱ) and 589.5 nm S (Ⅱ) lines can effectively characterize the surface cleaning quality of carbon fiber reinforced polymer in the plasma spectrogram. The cleaning threshold of single laser to remove the surface material completely is 10.68 mJ. Low laser energy can remove epoxy resin more than once. High laser energy can remove the surface resin with single laser, but multiple cleaning will damage the carbon fiber. These results provide basis and technical support for the intelligent integrated application of laser cleaning carbon fiber composites.